OIL NOZZLE FOR A TURBINE ENGINE

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an oil nozzle for a turbomachine, and in particular to an oil nozzle for spraying oil to lubricate and / or cool components such as the bearings of a turbomachine. It also relates to a turbomachine equipped with at least one such oil nozzle.

[0002] The invention has applications in the field of aeronautics and, in particular, in the field of lubrication of aeronautical engine parts such as turbomachine bearings. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] In aeronautics, it is a known practice to spray oil onto certain parts of turbomachinery to lubricate and / or cool them. Specifically, in a turbomachine, components such as bearings, gears, electric generators, etc., are lubricated by means of oil circulating in an oil circuit and injected by an oil nozzle towards the components to be lubricated, within an engine enclosure.

[0004] An example of a turbomachine engine enclosure is shown on the figure 1 . This figure 1The diagram shows a drive shaft 10 around which bearings 20 are mounted, providing a mechanical connection between the rotor and the stator of the motor. A first enclosure 30 surrounds the bearings 20 and ensures the circulation of the oil. A second enclosure 40 surrounds the first enclosure and pressurizes the oil within the first enclosure 30. In this example, the oil is sprayed towards the bearings 20, within the first enclosure 30, by an oil jet, schematically represented by reference numeral 100. The oil thus sprayed onto the bearings flows into the first enclosure 30 and is discharged by gravity into the collection channel 35 to be recycled and / or reinjected into the oil circuit.

[0005] To be effective, components, such as bearings, must be lubricated homogeneously with oil distributed as evenly as possible over them. However, the behavior of the oil jet projected onto the engine components to be lubricated varies depending on the aircraft's flight phase. In flight, the turbomachine shaft rotates at speeds that vary according to the flight phase. When the shaft's rotational speed is high, its rotation induces airflow that can affect the behavior of the injected oil jet, such as deflecting it. A deflection of the oil jet results in less precise and less dynamic targeting. The oil jet may not reach the intended component or may only reach a portion of it, which has a direct impact on engine operation and component lifespan.

[0006] In the aeronautical field, oil jets are often formed from a conduit or a set of conduits created by drilling into a blank. An example of an oil jet is shown in cross-section on the figure 2 In this example, the oil jet comprises a main conduit 110, for example a portion of an oil circuit, and a secondary conduit 120 connected to the main conduit. The secondary conduit 120, of length L and diameter D, has a first end 120a connected to the main conduit and a second open end 120b, through which the oil, under pressure, is projected towards the component to be lubricated.

[0007] Document EP3693651 A1 describes another example of a multi-duct sprinkler.

[0008] Because modern nozzles are manufactured with multiple perforations, sharp angles are created at the points where the nozzles connect, forming pointed edges between two perforations at the intersection of the nozzles. These edges cause instability in the oil flow. For example, at these points, the oil flow can cause separation, resulting in a low-pressure zone that can lead to cavitation and / or destabilize the oil jet by amplifying any irregularities in the oil flow. The oil flow is then no longer symmetrical, which can cause atomization of the oil jet, i.e., the jet breaking up into a diffuse spray.

[0009] He is depicted on the figure 3A diagram illustrates an example of pressure differences within a conventional oil nozzle. In this example, the oil flows through the main conduit 110 at a pressure P1 and then enters the secondary conduit 120 at a pressure that changes within the secondary conduit. The pressure P1 at the inlet of the secondary conduit 120, particularly in the upper part of the connection zone 130, changes to a pressure P2 near the lower part of the connection zone 130. This pressure difference between the different sections of the secondary conduit 120 generates, in this example, a vortex shedding zone LT (with a pressure P3) and a depression zone DP (with a pressure P4) within the secondary conduit. The oil flow in the secondary conduit 120 is therefore unstable, and this instability is reflected throughout the entire oil flow, even after it exits the secondary conduit.Indeed, the oil jet, after the 140 outlet of the 100 nozzle, exhibits pressure variations (VP) that result in poor oil jet quality, such as a bursting into a diffuse spray, known as atomization. However, an atomized oil jet is not only inconsistent and therefore of poor quality, but it is also particularly sensitive to air currents and can thus be easily deflected, leading to poor targeting of the components to be lubricated.

[0010] In the aeronautical field, it is known that problems of oil flow instability and atomization of the oil jet exiting the nozzle are addressed by increasing the nozzle's L / D ratio. A higher L / D ratio allows more time for the oil flow to stabilize before exiting the nozzle. However, increasing the L / D ratio directly impacts the nozzle's size, resulting in a larger overall dimensions.

[0011] However, nowadays, the environment within turbomachinery is increasingly constrained, necessitating a reduction in the size of the various parts and components within the turbomachinery, and in particular, the size of the nozzles. The solutions proposed to date are therefore contrary to the evolution of turbomachinery.

[0012] There is therefore a real need for an oil jet that allows the projection of a stable jet of oil, that is to say, a jet of oil which, at the time of its projection towards the parts to be lubricated, is free from any depression and / or imbalance, without the bulk of said jet being increased. SUMMARY OF THE INVENTION

[0013] To address the aforementioned problems of oil jet instability at the nozzle outlet, the applicant proposes an oil nozzle for the lubrication of turbomachine components whose internal wall of the connection area is curved and free of angularities.

[0014] According to a first aspect, the invention relates to an oil jet for the lubrication of components such as bearings within a turbomachine, comprising: a main oil supply line, at least one secondary oil outlet line through which the oil is sprayed onto the component, and a connection area between the secondary line and the main line having a junction angle between the main line and the secondary line, characterized in that the connection zone has an internal wall in contact with the oil, said internal wall being at least partially curved at the junction between the secondary conduit and the main conduit so that the junction angle inside the connection zone is at least partially rounded.

[0015] Due to the absence of angularity at the junction between the main and secondary conduits, this nozzle allows for a smooth flow of oil, which reduces the risk of unsteady oil flow phenomena in the secondary conduit and ensures a consistent oil jet at the nozzle outlet.

[0016] An internal wall, as opposed to an external wall, is a wall located inside conduits and therefore in contact with the oil circulating in the oil jet.

[0017] In addition to the characteristics mentioned in the preceding paragraph, the oil jet according to one aspect of the invention may have one or more additional characteristics from among the following, considered individually or in all technically possible combinations: The inner wall in contact with the oil has a bulge extending over at least a portion of the circumference of the junction angle between the secondary and primary conduits. The inner wall has a shape determined by a diameter of the secondary conduit, a value of the junction angle between the primary and secondary conduits, and / or an L / D ratio, where D is the diameter of the secondary conduit and L is its length. The junction angle between the primary and secondary conduits is obtuse, depending on the direction of oil flow. The curved shape of the inner wall is achieved by additive manufacturing. The curved shape of the inner wall is achieved by adding an annular piece fixed inside the connection area. The curved shape of the inner wall is achieved by drilling a blank.The secondary and / or main conduit is made of a flexible material capable of adapting to the oil flow circulating in said conduits, the main and / or secondary conduit made of flexible material being held by an attachment system on a structure of the turbomachine.

[0018] Another aspect of the invention relates to a turbomachine, characterized in that it comprises at least one oil jet as defined above. BRIEF DESCRIPTION OF THE FIGURES

[0019] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which: There figure 1 The diagram, already described, represents a schematic cross-sectional view of an example of a turbomachine engine enclosure equipped with an oil jet; figure 2 The figure already described represents a schematic cross-sectional view of an oil jet according to the prior art; figure 3The diagram, already described, schematically represents a variation in oil flow pressure within a nozzle according to the prior art and at the nozzle outlet; figure 4 represents a schematic cross-sectional view of an example of an oil jet according to the invention; The figure 5 represents a schematic cross-sectional view of another example of an oil jet according to the invention; and The figure 6 represents, according to a schematic cross-section, two examples of annular parts intended to be fixed in the connection area of ​​an oil jet according to the invention. DETAILED DESCRIPTION

[0020] An example of an embodiment of an oil nozzle, configured to limit the instability of the oil flow in the nozzle's secondary channel, is described in detail below, with reference to the accompanying drawings. This example illustrates the features and advantages of the invention. It should be noted, however, that the invention is not limited to this example.

[0021] In the figures, identical elements are identified by identical references. For the sake of readability, the size scales between represented elements are not respected.

[0022] An example of an oil jet according to the invention is shown on the figure 4This oil nozzle 200 comprises a main conduit 210, for example, a portion of an oil circuit, and a secondary conduit 220 connected to the main conduit 210 at a region called the connection zone 230. The main conduit 210 and secondary conduit 220 are channels designed to carry oil from the oil circuit to the outlet 240 of the nozzle 200, from where it is sprayed to the components to be lubricated. The secondary conduit 220 has a first end 220a connected to the main conduit 210 and a second open end 220b, through which the oil, under pressure, is sprayed to the component to be lubricated, for example, a bearing. At the junction between the secondary conduit and the main conduit, i.e., at the opening of the secondary conduit, the connection zone 230 has an angle, called the junction angle.This angle is preferably, depending on the direction of oil flow, an obtuse angle suitable to ensure oil flow with a chosen pressure.

[0023] The oil nozzle according to the invention comprises, in the connection zone 230 of the secondary conduit 220 to the main conduit 210, a curved internal wall 235, forming a rounded shape over at least a portion of the junction angle, inside the connection zone 230. Indeed, as shown in the figure 4 , the internal wall 235 has a curve of a predefined shape, adapted to limit or eliminate sharp edges or angular projections inside the connection area 230, in the vicinity of the junction angle.

[0024] According to certain embodiments of the invention, the inner wall 235 has a curved shape extending over the entire circumference of the junction angle between the secondary conduit 220 and the main conduit 210, such that the entire junction angle is rounded. In these embodiments, the junction angle no longer has any angular projections or sharp edges that could generate instability in the oil flow.

[0025] In other embodiments, the inner wall 235 has a curved shape extending over only a portion of the circumference of the junction angle between the secondary conduit 220 and the main conduit 210. In these embodiments, the curved portion of the junction angle extends over the part of the junction angle that has the greatest impact on the oil pressure upon entry into the secondary conduit and therefore the greatest risk of generating disturbances in the oil flow. Thus, by limiting the angular projections to the areas of the junction angle least likely to create disturbances, the risks of oil flow instability are reduced.

[0026] In some embodiments, the inner wall 235 has a bulge extending around the entire circumference of the junction between the secondary and main conduits, or only over a portion of this circumference. This bulge, which can be obtained by various methods described later, has the effect of covering a salient angle so that the oil is no longer in contact with said salient angle but with the bulge. These embodiments have the advantage of allowing the main and secondary conduits to be manufactured using the conventional drilling technique, with the addition of the bulge being a subsequent operation performed on existing conduits.

[0027] In some embodiments of the invention, the outer wall of the connection zone 230, i.e. the wall which is not in contact with the oil, can also be curved with a shape identical or different from the shape of the inner wall 235.

[0028] The fact that at least part of the junction angle between the main conduit 210 and the secondary conduit 220 is rounded, and therefore devoid of sharp edge or angular protrusion, facilitates the flow of oil within the nozzle, which helps to avoid detachments and limit unsteady phenomena of the oil flow in the secondary conduit 220.

[0029] Like any nozzle, the secondary conduit 220 of the oil nozzle 200 has a length L and a diameter D. The details of the curved shape of the inner wall 235, for example its curvature, can be determined based on the junction angle, the diameter D of the secondary conduit 220, the L / D ratio, etc. For example, the radius of curvature of the inner wall 235 will be smaller for a junction angle of 90° than for a junction angle of 120°. An optimal shape of the inner wall 235 can be determined by topological optimization using simulation tools, for example, CFD (Computational Fluid Dynamics), or by testing a range of technological solutions. An optimal shape of the inner wall 235 can result in a minimum length L of the secondary conduit 220 and, consequently, a minimum lateral footprint for the oil nozzle.

[0030] The curved, or rounded, shape of the inner wall 235 can be achieved by various manufacturing processes. For example, it can be achieved by additive manufacturing, by depositing one or more layers of material over and / or around the joint angle, inside the connecting area 230. Such an additive manufacturing technique makes it possible, for example, to create a bulge or a particular shape of the connecting area.

[0031] According to another variant, the curved shape of the inner wall 235 can be obtained by adding a specific part inside the nozzle, in the connection area 230. An example of a nozzle 200 equipped with such a specific part 250 is schematically shown on the figure 5This specific part 250 can be an annular part, or channel, housed in the secondary conduit 220, at its intersection with the main conduit 210, at the junction angle. This annular part 250 can be configured, as in example A of the figure 6 , in the form of a ring having a flat outer face 250a, intended to be in contact with the inner face 220b of the secondary conduit 220, and a domed inner face 250b, intended to be in contact with the oil flow. Alternatively, the annular part 250 may be presented, as in example B of the figure 6in the form of a half-ring comprising a flat outer face 250a, intended to be in contact with the inner face 220b of the secondary conduit 220, a domed inner face 250b, intended to be in contact with the oil flow, and a flat transverse face 250c forming the nozzle outlet face. This annular piece can be fixed inside the connection area 230 by any fastening method known in the field, such as welding, brazing, or screwing.

[0032] According to one embodiment of the invention, the secondary conduit 220 and / or the main conduit 210 is made of a flexible material capable of adapting to the oil flow circulating in said conduits and exhibiting good heat resistance. The flexible material has the advantage of having a curved joint, without any angularity. In this embodiment, the flexible material conduit(s) is / are held by a fastening system mounted on a surrounding structure, such as, for example, an engine housing.

[0033] Regardless of the specific embodiment of the nozzle according to the invention, the smoother the oil flow is at the points of change of direction, i.e., in the connection zone 230, without any roughness or angularity, the lower the risk of separation and disturbances. This ensures a stable flow of oil in the secondary conduit 220 and therefore a consistent spray pattern at the nozzle outlet 240. Consequently, atomization and / or poor targeting are significantly reduced, or even eliminated. The secondary conduit 220 of the oil nozzle according to the invention can therefore have a shorter length L than in conventional nozzles, since this length is no longer required to stabilize the oil flow before it exits the nozzle.

[0034] Although described through a number of examples, variants and embodiments, the oil jet according to the invention includes various variants, modifications and improvements which will be obvious to a person skilled in the art, it being understood that these variants, modifications and improvements are part of the scope of the invention as defined by the claims.

Claims

1. An oil nozzle (200) for lubricating members such as bearings within a turbomachine, comprising: - a main oil supply duct (210), - at least one secondary oil outlet duct (220) through which oil is sprayed onto the member, and - a connection zone (230) for connecting the secondary duct to the main duct, including a junction angle (260) between the main duct and the secondary duct, characterised in that the connection zone (230) includes an inner wall (235) in contact with oil, said inner wall (235) being at least partially curved at the junction between the secondary duct and the main duct so that the junction angle (260) inside the connection zone is at least partially rounded, said inner wall (235) including a bulge (250) extending over at least one portion of the circumference of the junction angle between the secondary duct (220) and the main duct (210).

2. The oil nozzle according to claim 1, characterised in that the inner wall (235) includes a curved shape whose characteristics are determined based on a diameter of the secondary duct (220), a value of the junction angle (260) between the main duct and the secondary duct and / or a ratio L / D, where D is the diameter of the secondary duct and L is its length.

3. The oil nozzle according to any of claims 1 to 2, characterised in that the junction angle (260) between the main duct (210) and the secondary duct (220) is, along the oil flow direction, an obtuse angle.

4. The oil nozzle according to any of claims 1 to 3, characterised in that a curved shape of the inner wall (235) is obtained by additive manufacturing.

5. The oil nozzle according to any of claims 1 to 3, characterised in that a curved shape of the inner wall (235) is obtained by adding an annular part attached inside the connection zone.

6. The oil nozzle according to any of claims 1 to 3, characterised in that a curved shape of the inner wall (235) is obtained by drilling a blank.

7. A turbomachine, characterised in that it includes at least one oil nozzle (200) according to any of claims 1 to 6.